Cancer outlook: an African perspective.

In all western populations, mortality rates from cancer are high and even increasing: moreover, incidence rates of some cancers are also rising. As to propitiousness of preventive factors, genetic, gender, and age are beyond alteration: much the same applies to certain protective factors, e.g. late menarche, teenage pregnancy, high parity, long lactation, and greater physical activity. Influential dietary factors, i.e. intakes of energy, fat and fibre, often do not lend themselves to major alteration. Although reductions in smoking have occurred, the practice remains widespread and the intake of alcohol remains high. In developing countries, such as Africa, life-style changes are occurring and the population is incurring all risk factors mentioned. Whereas cancer is relatively uncommon in rural dwellers in developing countries, it is increasing in the huge peri-urban and urban populations due to changes in diet and way of life. Although knowledge should enable us to halve cancer's burden, hopes for meaningful changes are meagre. Survival time can be lengthened by more effective screening, especially of the very susceptible, and by further advances in treatment. Since known risk factors account for only half or less of occurrences of cancer, further rises, or, hopefully, welcome falls, could conceivably occur in the future. We must continue to try to educate the public regarding cancer avoidance: compliance by even a small proportion of those at risk could benefit huge numbers.